The present invention pertains to apparatus for rapidly spooling magnetic tape onto spools of the type used in endless tape cartridges.
Because of their compact size, and endless operation in one direction of tape advancement, endless magnetic tape cartridges are becoming increasingly popular for both pre-recorded material and blank tapes. There are several existing configurations for endless tape cartridges, but in general they all employ the basic design feature of a single, centrally disposed spool shaped to enable the innermost tape winding to be withdrawn from a position adjacent the hub and from there, guided in an intricate guide path past one or more apertures in the cartridge housing for contact with the magnetic heads, capstan and pinch roller, and hence wound back onto the spool as the outermost winding. For example, one such cartridge configuration is disclosed in U.S. Pat. No. 3,420,461, entitled "Endless Magnetic Tape Cartridge," issued Jan. 7, 1969 to R. P. Cousino. In that cartridge, the inner tape winding is guided around obliquely oriented tape guides which position the plane of the tape, for contact with the magnetic heads, at right angles to the orientation of the tape when wound on the spool. The change in the orientation of the tape results in a more compact cartridge and thus is preferred for many applications.
In endless tape cartridges of the type disclosed in the above-mentioned patent, and in other cartridges of similar design, the unique manner in which the tape is continuously fed from the inner winding to the outer winding requires that the tape be wound onto the spool at a spooling tension that is maintained within a narrow, predetermined range. Too little tension will result in sloppy movement of the tape within the cartridge, while too much tension will inhibit easy, smooth withdrawal of the inner winding of tape from a position adjacent the hub. Thus, the cartridge spools are normally, factory wound under conditions which enable the spooling tension to be carefully regulated. For example, one type of preferred spooling apparatus entails the feeding of a single strand of tape, the tension of which is continuously controlled within preset limits, onto a series of empty spools arranged in a row along a common takeup shaft which is rotated at a controlled speed. As each spool is filled, a tape supply guide is shifted axially relative to the row of spools, causing the continuous strand of tape to pass over a rim of the filled spool and commence winding onto the hub of the adjacent spool. After the last spool in the row is filled, the spooling operation is interrupted and the operator cuts the strands of tape connecting adjacent spools, and removes the spools from the takeup shaft. The spooling tension is controlled by monitoring the position of a tape engaging compliance arm and responsively controlling the tension of the single strand of tape between the supply reel and the spool. It is evident that this serial feed spooling technique simplifies the tension control requirement since it is necessary to monitor the tension in only one strand of tape.
Another advantage of this single strand, serial spooling apparatus is that it requires only minimal handling of the strand of tape by the operator. He must thread the tape onto the first spool. However, thereafter the tape is automatically advanced, in an uninterrupted strand, to the succeeding spools. For many tape cartridges, the tape is so thin, and of such small width, that handling of the tape by the operator is extremely tedious, and frequently leads to twisting and tangling of the tape which decreases productivity.
For the above reasons, the serial spooling type of equipment is currently preferred and is predominantly used throughout the industry. However, because the spooling rate of this type of apparatus is limited to the rate of advancement of a single strand of tape, the process of filling the entire row of spools is time consuming, even when the tape is advanced at a rate many times greater than the playback-record speed. In many tape cartridge production facilities, the spooling time has become a limiting factor in improving the productivity.
One possible solution to stepping up the spooling speed is to wind a plurality of spools simultaneously, by feeding the tape in parallel strands from a plurality of supply reels. While the desirability of a parallel spooling apparatus is apparent, its implementation gives rise to numerous problems, some foreseeable, others less apparent. One problem is that each strand of tape requires a separate tension control, which could be accomplished by duplicating the above-mentioned compliance arm device for each parallel feed path. Such duplication, because of its expense and cumbersomeness, greatly detracts from the speed advantage of a parallel spooler. Moreover, parallel spooling means a substantial increase in the amount of tape handling that must be performed by the operator. After filling each set of spools, cutting the tape and removing the filled spools, the operator must thereupon insert and individually thread the plurality of empty spools prior to the next winding operation. In sum, any advantage in terms of increased spooling speed would be negated by disadvantages and the cost and complexity of the equipment, and in the increase manipulation required of the individual tape strands.
Accordingly, it is an object of the invention to provide an apparatus for increasing the speed of spooling magnetic tape onto spools of the type used in endless tape cartridges, while providing suitable control over the spooling tension of the tape, and without significantly increasing the amount of tape handling that must be performed by the operator of the apparatus.
More specifically, it is an object to provide a multiple-spool, parallel-feed tape spooling apparatus for concurrently winding, in parallel, a plurality of spools of the above-mentioned type, and having suitable control over the spooling tension of the tape and minimizing the amount of handling of the tape that must be performed by the operator of the apparatus. A related object is to provide precision control of the spooling tension without resorting to expensive, cumbersome, duplicative use of compliance arm tension controllers of the type currently used in serial spooling equipment.
Still another object is to provide a multiple-spool, parallel-feed spooling apparatus as above which is capable of filling spools either according to the amount of playback-record time, or according to cue signals prerecorded at intervals along the strands of supply tape.